U.S. patent number 8,764,090 [Application Number 13/667,134] was granted by the patent office on 2014-07-01 for vehicles incorporating tailgate energy management systems.
This patent grant is currently assigned to Toyota Motor Engineering & Manufacturing North America, Inc.. The grantee listed for this patent is Toyota Motor Engineering & Manufacturing North America, Inc.. Invention is credited to Norman C. Kerr.
United States Patent |
8,764,090 |
Kerr |
July 1, 2014 |
Vehicles incorporating tailgate energy management systems
Abstract
A vehicle includes sidewalls, a tailgate located proximate to
rear ends of the sidewalls, and a tailgate energy management
system. The tailgate energy management system includes a governor
coupled to one of the sidewalls and to the tailgate. The governor
selectively applies a governing force to the tailgate to reduce an
opening speed of the tailgate. The tailgate energy management
system also includes a speed sensor sensing an opening speed of the
tailgate and an electronic control unit electronically coupled to
the governor and the speed sensor. The electronic control unit
includes a processor and memory storing an instruction set. The
electronic control unit receives a speed signal indicative of the
opening speed of the tailgate and the processor executes the
instruction set to cause the electronic control unit to transmit a
control signal to the governor to slow the opening speed of the
tailgate based on the speed signal.
Inventors: |
Kerr; Norman C. (Ann Arbor,
MI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Toyota Motor Engineering & Manufacturing North America,
Inc. |
Erlanger |
KY |
US |
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Assignee: |
Toyota Motor Engineering &
Manufacturing North America, Inc. (Erlanger, KY)
|
Family
ID: |
47753766 |
Appl.
No.: |
13/667,134 |
Filed: |
November 2, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
|
US 20130060403 A1 |
Mar 7, 2013 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13207787 |
Aug 11, 2011 |
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Current U.S.
Class: |
296/50;
296/146.4; 296/57.1 |
Current CPC
Class: |
E05F
15/627 (20150115); E05Y 2400/36 (20130101); E05Y
2900/544 (20130101) |
Current International
Class: |
B62D
33/03 (20060101) |
Field of
Search: |
;296/50-62,146.8,146.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Dayoan; Glenn
Assistant Examiner: Blankenship; Gregory
Attorney, Agent or Firm: Dinsmore & Shohl LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of application Ser. No.
13/207,787 filed Aug. 11, 2011.
Claims
What is claimed is:
1. A method of managing remote actuation of a vehicle tailgate
comprising: receiving a command to open the tailgate; transmitting
an unlatch signal to at least one tailgate latch actuator to
unlatch a tailgate latch from a corresponding tailgate latch
striker; applying an unlatch force to the tailgate latch that is
smaller than a predetermined maximum unlatch force; and terminating
the unlatch signal to the at least one tailgate latch actuator if
an external load applied to the tailgate is greater than a
predetermined maximum external load.
2. The method of managing remote actuation of the vehicle tailgate
of claim 1, wherein the at least one tailgate latch actuator
applies an unlatch force to the tailgate latch.
3. The method of managing remote actuation of the vehicle tailgate
of claim 2, wherein the unlatch force applied by the at least one
tailgate latch actuator to the tailgate latch is greater than an
internal resistance of the tailgate latch when the external load
applied to the tailgate is smaller than the predetermined maximum
external load.
4. The method of managing remote actuation of the vehicle tailgate
of claim 1, wherein the external load applied to the tailgate
increases an internal resistance of the tailgate latch.
5. The method of managing remote actuation of the vehicle tailgate
of claim 4, wherein the unlatch force applied by the at least one
tailgate latch actuator to the latch is greater than the internal
resistance of the tailgate latch when the external load applied to
the tailgate is less than the predetermined maximum external
load.
6. The method of managing remote actuation of the vehicle tailgate
of claim 5, wherein the unlatch force applied by the at least one
tailgate latch actuator is less than the internal resistance of the
tailgate latch when the external load applied to the tailgate is
greater than the maximum external load.
7. A vehicle comprising: a tailgate latch coupled to one of a
vehicle tailgate or sidewalls of a vehicle; a tailgate latch
striker coupled to one of the vehicle tailgate or sidewalls of the
vehicle, the tailgate latch and the tailgate latch striker
positioned to selectively latch with one another; a tailgate latch
actuator coupled to the tailgate latch that selectively applies an
unlatch force to the tailgate latch, the unlatch force being
smaller than a predetermined maximum latch force that corresponds
to a predetermined maximum external load applied to the tailgate,
wherein if an external load applied to the tailgate is greater than
the predetermined maximum external load, the tailgate latch remains
latched to the tailgate latch striker; and a command device
communicatively coupled to the tailgate latch actuator, the command
device configured to provide an unlatch signal to the tailgate
latch actuator.
8. The vehicle of claim 7, further comprising an electronic control
unit communicatively coupled to the tailgate latch actuator, the
electronic control unit comprising a processor and a memory storing
a computer readable instruction set that, when executed by the
processor, receives the unlatch signal from the command device and
transmits a signal to the tailgate latch actuator to apply the
unlatch force to the tailgate latch.
9. The vehicle of claim 8 further comprising a governor coupled to
one of the sidewalls and to the tailgate, the governor selectively
applying a governing force to the tailgate to reduce an opening
speed of the tailgate.
10. The vehicle of claim 9 further comprising a speed sensor
communicatively coupled to the electronic control unit sensing the
opening speed of the tailgate, wherein the electronic control unit
receives a speed signal indicative of the opening speed of the
tailgate from the speed sensor and the processor executes the
instruction set to cause the electronic control unit to transmit a
control signal to the governor such that the governor slows the
opening speed of the tailgate based on the speed signal.
11. The vehicle of claim 7, wherein the command device comprises a
wireless receiver communicatively coupled to the electronic control
unit, the wireless receiver receives a wireless command signal to
open the tailgate, the wireless receiver relays the wireless
command signal to the tailgate latch actuator to command the
tailgate latch actuator to apply the unlatch force to the tailgate
latch.
12. A method of managing remote actuation of a vehicle tailgate
comprising: receiving a command to open the tailgate; transmitting
an unlatch signal to at least one tailgate latch actuator to
unlatch a tailgate latch from a corresponding tailgate latch
striker; and applying an unlatch force to the tailgate latch that
is smaller than a predetermined maximum unlatch force that
corresponds to a maximum external load applied to the tailgate,
wherein when an external load applied to the tailgate exceeds the
maximum external load the tailgate latch remains latched to the
striker.
13. The method of managing remote actuation of the vehicle tailgate
of claim 12, further comprising terminating the unlatch signal to
the at least one tailgate latch actuator if the external load
applied to the tailgate is greater than the maximum external
load.
14. The method of managing remote actuation of the vehicle of claim
12, wherein the external load applied to the tailgate latch
increases an internal resistance of the tailgate latch.
15. The method of managing remote actuation of the vehicle of claim
14, wherein the unlatch force applied by the at least one tailgate
latch actuator to the tailgate latch is greater than the internal
resistance of the tailgate latch when the external load applied to
the tailgate is less than the maximum external load.
16. The method of managing remote actuation of the vehicle of claim
15, wherein the unlatch force applied by the at least one tailgate
latch actuator is less that the internal resistance of the tailgate
latch when the external load applied to the tailgate is greater
than the maximum external load.
Description
TECHNICAL FIELD
The present disclosure is generally directed to tailgate energy
management systems for vehicles and vehicles incorporating tailgate
energy management systems that limit the opening speed of
tailgates.
BACKGROUND
Vehicles having deployable tailgates, for example, pickup trucks,
passenger vans, and sport utility vehicles (SUVs), may include lift
assist devices that reduce the amount of force required to be
applied by a user to control the motion of the tailgates as they
are moved between open and closed positions. The lift assist
devices may include gas dampers and/or torsion springs that apply a
direction force to the tailgate that allows for easier opening
and/or closing of the tailgate.
However, lift assist devices may not apply a force of variable
intensity to accommodate a variety of conditions that the vehicle
may be subject to. Using a pickup truck as an example, the opening
speed (and therefore opening energy) of a tailgate may vary
depending on vehicle inclination, ambient temperature, and/or gas
damper wear. The variability in opening energy may be problematic
in applications where the user chooses to open a tailgate while at
a remote location, for example, when using a remote keyless entry
system. In such an application, tailgates that contact surrounding
objects while opening with energy greater than a predefined
threshold energy may cause damage to the tailgate and/or the
surrounding object.
Accordingly, vehicles incorporating tailgate energy management
systems are desired.
SUMMARY
In one embodiment, a vehicle includes sidewalls spaced laterally
apart from one another, a tailgate located proximate to rear ends
of the sidewalls, and a governor coupled to one of the sidewalls
and to the tailgate. The governor selectively applies a governing
force to the tailgate to reduce an opening speed of the tailgate.
The vehicle also includes a speed sensor sensing an opening speed
of the tailgate and an electronic control unit electronically
coupled to the governor and the speed sensor. The electronic
control unit includes a processor and memory storing a computer
readable and executable instruction set. The electronic control
unit receives a speed signal indicative of the opening speed of the
tailgate from the speed sensor and the processor executes the
instruction set to cause the electronic control unit to transmit a
control signal to the governor such that the governor slows the
opening speed of the tailgate based on the speed signal.
In another embodiment, a vehicle includes sidewalls spaced
laterally apart from one another, a tailgate located proximate to
rear ends of the sidewalls, and a retractable cable assembly having
a cable coupled to the tailgate and a rotatable drum about which
the cable is wound. The vehicle also includes a governor coupled to
the sidewalls and to the rotatable drum, where the governor
selectively applies a governing force to the tailgate through the
rotatable drum to slow an opening speed of the tailgate.
In yet another embodiment, a tailgate energy management system for
controlling an opening speed of a tailgate relative to sidewalls of
a vehicle includes a governor coupled to one of the sidewalls and
to the tailgate, where the governor selectively applies a governing
force to the tailgate that reduce the opening speed of the
tailgate. The tailgate energy management system also includes a
speed sensor sensing an opening speed of the tailgate and an
electronic control unit electronically coupled to the governor and
the speed sensor. The electronic control unit includes a processor
and memory storing a computer readable and executable instruction
set. The electronic control unit receives a speed signal indicative
of the opening speed of the tailgate from the speed sensor and the
processor executes the instruction set to cause the electronic
control unit to transmit a control signal to the governor such that
the governor slows the opening speed of the tailgate based on the
speed signal.
These and additional features provided by the embodiments described
herein will be more fully understood in view of the following
detailed description, in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments set forth in the drawings are illustrative and
exemplary in nature and not intended to limit the subject matter
defined by the claims. The following detailed description of the
illustrative embodiments can be understood when read in conjunction
with the following drawings, where like structure is indicated with
like reference numerals and in which:
FIG. 1 depicts a perspective view of a vehicle including a tailgate
energy management system according to one or more embodiments shown
and described herein;
FIG. 2 depicts a cut-away side view of a vehicle including a
tailgate energy management system according to one or more
embodiments shown and described herein;
FIG. 3 depicts a rear view of the vehicle including a tailgate
energy management system of FIG. 2 along line A-A;
FIG. 4 depicts a rear view of the tailgate energy management system
of FIG. 2 along line B-B;
FIG. 5 depicts a cut-away side view of a vehicle including a
tailgate energy management system according to one or more
embodiments shown and described herein;
FIG. 6 depicts a rear view of the vehicle including a tailgate
energy management system of FIG. 5 along line C-C;
FIG. 7 depicts a side view of a vehicle including a tailgate energy
management system according to one or more embodiments shown and
described herein; and
FIG. 8 depicts a cut-away side view of a vehicle including a
tailgate energy management system according to one or more
embodiments shown and described herein.
DETAILED DESCRIPTION
Embodiments described herein relate to vehicles having tailgate
energy management systems that limit the opening energy of the
tailgates. Referring to FIG. 1, one embodiment of a vehicle with a
tailgate energy management system is schematically depicted. The
vehicle includes a tailgate located proximate to the rear ends of
the sidewalls of the vehicle. A governor is coupled to one of the
sidewalls and to the tailgate. An electronic control unit works in
conjunction with the governor to selectively apply a governing
force to the tailgate. The governing force reduces the opening
speed of the tailgate. The electronic control unit receives a speed
signal from a speed sensor that indicates the opening speed of the
tailgate. The electronic control unit transmits a control signal to
the governor causing the governor to apply the governing force to
the tailgate based on the speed signal. Embodiments of the tailgate
energy management system and vehicles incorporating the same will
be described in more detail herein.
Referring now to FIG. 1, one embodiment of a vehicle 80 including a
tailgate energy management system 100 is shown. The vehicle 80
includes two sidewalls 92 spaced laterally apart from one another.
A tailgate 90, illustrated in an open position, is located
proximate to the rear ends 93 of the sidewalls 92. The tailgate
energy management system 100 includes a governor 110 coupled to one
of the sidewalls 92 of the vehicle 80. The tailgate energy
management system 100 also includes an electronic control unit 200
electronically coupled to the governor 110 and to a speed sensor
210. The speed sensor 210 transmits a speed signal that is received
by the electronic control unit 200. The speed signal corresponds to
the opening speed of the tailgate 90. The speed sensor 210 may be a
Hall Effect sensor or a similar sensor for determining the
rotational speed of a component. The speed sensor 210 may determine
the rotational rate of the retractable cable assembly 120 or the
linear speed of travel of the cable 122 coupled to the tailgate
90.
As used herein, governor 110 is a clutch assembly or a brake
assembly that applies a force to a proximate component of the
tailgate energy management system 100 to slow or stop the movement
of the proximate component. In the embodiment described herein, the
governor 110 is electronically actuated by a control signal
transmitted from the electronic control unit 200 and received by
the governor 110. When the governor 110 receives the control signal
from the electronic control unit 200, the governor 110 applies a
force to the proximate component of the tailgate energy management
system 100 such that the force reduces the opening speed of the
tailgate 90. An example of such an electronically actuated governor
110 is an electromagnetic clutch or electromagnetic brake available
from Ogura Industrial Corp. of Somerset, N.J. In the alternative,
the governor 110 may be mechanically controlled and actuated.
Examples of such a mechanically controlled and actuated governor
110 may include a centrifugal clutch or brake that engages a
proximate component of the tailgate energy management system 100
when the speed of rotation of the centrifugal clutch or brake
exceeds a threshold speed.
In the embodiment depicted in FIG. 1, the tailgate energy
management system 100 further includes a retractable cable assembly
120 that includes a cable 122 and a rotatable drum 124. The cable
122 is coupled to the tailgate 90 and is wound about the rotatable
drum 124. The rotatable drum 124 pays out the cable 122 as the
tailgate 90 rotates from a closed position (as depicted in FIG. 7)
to an open position (as depicted in FIG. 1). Additionally, the
rotatable drum 124 collects the cable 122 and winds the cable 122
about the rotatable drum 124 as the tailgate 90 rotates from an
open position to a closed position.
The vehicle 80 may also include an over-travel cable 96 coupled to
both the sidewall 92 and to the tailgate 90. The over-travel cable
96 supports the tailgate 90 when the tailgate 90 is in the open
position and stops the tailgate 90 from rotating. As shown in FIG.
1, the over-travel cable 96 stops the tailgate 90 from rotating and
holds the tailgate 90 in an approximately horizontal
orientation.
The vehicle 80 also includes at least one tailgate latch 70 and a
corresponding tailgate latch striker 72. The vehicle 80 depicted in
FIG. 1 includes two tailgate latches 70 positioned along opposite
sides of the tailgate 90 proximate to each of the sidewalls 92.
When the tailgate 90 is located in the closed position, the
tailgate latches 70 interface with the tailgate latch striker 72,
thereby securing the tailgate 90 to the sidewalls 92 of the vehicle
80 and maintaining the tailgate 90 in a closed position. The
tailgate latches 70 and the tailgate latch strikers 72 maintain the
tailgate 90 in the closed position until the tailgate latches 70
are actuated to decouple from one another. While the embodiment of
FIG. 1 depicts the tailgate latch 70 as being positioned along the
tailgate 90 and the tailgate latch strikers 70 positioned along the
sidewalls 92 of the vehicle 80, it should be understood that the
relative positions of the tailgate latches 70 and the tailgate
latch strikers 72 with respect to the tailgate 90 and the sidewalls
92 of the vehicle 80 may be modified without departing from the
scope of this disclosure.
Referring to FIG. 8, the tailgate latches 70 are actuated to
release themselves from the tailgate latch strikers 72, thereby
releasing the tailgate 90 from the closed position relative to the
sidewalls 92 of the vehicle 80. The tailgate latches 70 may be
actuated by a variety of methods including, for example and without
limitation, manual actuation of a remotely-located latch release or
automated actuation, for example actuated by a tailgate latch
actuator 74. In the embodiment depicted in FIG. 8, the tailgate
latch actuator 74 is a linearly-acting actuator, however, other
embodiments of tailgate latch actuators are contemplated including
rotary-acting actuators. In some embodiments, the tailgate latch
actuator 74 may be coupled to the latch 70 through a force
transmission mechanism (not shown), for example a Bowden cable or a
linkage, thereby allowing the tailgate latch actuator 74 to be
position and oriented at various locations within the vehicle 80
while continuing to provide force to actuate the tailgate latch 70.
In some embodiments, a single tailgate latch actuator 74 may be
coupled to tailgate latches 70 positioned along opposite sides of
the tailgate 90 (as depicted in FIG. 1), such that the single
tailgate latch actuator 74 actuates both tailgate latches 70.
As conventionally known, the tailgate latch 70 includes an internal
resistance that prevents the tailgate latch 70 from spontaneously
opening, thereby allowing the tailgate latch 70 from becoming
disengaged from the tailgate latch striker 72 unless so actuated.
To release the tailgate 90 from the closed position relative to the
sidewalls 92 of the vehicle 80, the tailgate latches 70 are
selectively unlatched from the tailgate latch strikers 72, thereby
decoupling the tailgate latches 70 from the tailgate latch strikers
72. The tailgate latch actuator 74 applies an unlatching force to
the tailgate latch 70 as to disengage the tailgate latch 70 from
the tailgate latch striker 72. The unlatching force is greater than
the internal resistance of the tailgate latch 70 such that the
unlatching force overcomes the internal resistance of the tailgate
latch 70.
In some embodiments, the kinetic energy that the tailgate 90 opens
with may be increased with the addition of an external force and/or
mass applied to the tailgate 90 in a direction that the tailgate 90
opens from the sidewalls 92 of the vehicle 80. In one example, such
external load may be applied to the tailgate 90 by cargo positioned
within the bed of the vehicle 80. As discussed hereinabove, the
tailgate energy management system 100 mitigates the kinetic energy
with which the tailgate 90 opens. Increasing the kinetic energy of
the tailgate 90 through the addition of an external force and/or
mass may be undesired. Further, the increase in kinetic energy of
the tailgate 90 through the addition of external force and/or mass
may reduce the effectively of the components of the tailgate energy
management system 100 such that the tailgate energy management
system cannot reduce the kinetic energy of the tailgate 90 to a
desired level. Accordingly, components that prevent the tailgate 90
from opening when an external load and/or mass is applied to the
tailgate 90 may be desired.
In some embodiments of the tailgate latch 70, the internal
resistance of the tailgate latch 70 may increase when an external
force and/or mass is applied to the tailgate 90. The external force
and/or mass applied to the tailgate 90 is reacted through the
tailgate latch 70 and the tailgate latch striker 72, thereby
increasing the force applied by the tailgate latch 70 onto the
tailgate latch striker 72 in the opening direction of the tailgate
90. This increase in force between the tailgate latch 70 and the
tailgate latch striker 72 may increase the internal resistance of
the tailgate latch 70. An increase in the internal resistance of
the tailgate latch 70 may require that the tailgate latch actuator
74 applies an increased latch actuation force to release the
tailgate latch 70 from the tailgate latch striker 72. To prevent
opening of the tailgate 90 when an external force and/or mass is
applied to the tailgate 90 that exceeds a predetermined maximum
external load applied to the tailgate 90, the maximum latch
actuation force of the tailgate latch actuator 74 may be actively
or passively controlled such that the tailgate latch actuator 74
provides an unlatch force capable of unlatching the tailgate latch
70 from the tailgate latch striker 72 when no external force and/or
mass is applied to the tailgate 90 and is not capable of unlatching
the tailgate latch 70 from the tailgate latch striker 72 when an
external force and/or mass is applied to the tailgate 90.
In some embodiments, an end-user of the vehicle 80 may provide a
command to command device 230 to open the tailgate 90. In some
embodiments, the command device 230 may be incorporated into the
electronic control unit 200. In other embodiments, the command
device 230 may be incorporated into a secondary electronic control
module (not shown). In still other embodiments, the command device
230 may be a relay, which may be communicatively isolated from the
electronic control unit 200. In some embodiments, the end-user may
provide the command to open the tailgate 90 by toggling a switch
(not shown), for example, a vehicle body or cabin-mounted switch,
that is communicatively coupled to the command device 230. In other
embodiments, the end-user may provide the command to open the
tailgate 90 by depressing a button on a radio transmitting device
(not shown). The radio transmitting device provides a wireless
signal, which is received by a wireless receiver 220 that is
communicatively coupled to the command device 230.
After receiving the command to open the tailgate 90 from the
end-user, the command device 230 may provide an unlatch signal to
the tailgate latch actuator 74, thereby commanding the tailgate
latch actuator 74 to apply the unlatch force to the tailgate latch
70 as to unlatch the tailgate latch 70 from the tailgate latch
striker 72. As described hereinabove, the tailgate latch actuator
74 provides an unlatch force to the tailgate latch 70 that is
smaller than a predetermined maximum unlatch force. By applying an
unlatch force that is less than the predetermined maximum unlatch
force, the tailgate latch actuator 74 unlatches the tailgate latch
70 from the tailgate latch striker 72 when external force and/or
mass is applied to the tailgate 90 is less than a predetermined
maximum external load, and does not unlatch the tailgate latch 70
from the tailgate latch striker 72 when external force and/or mass
is applied to the tailgate 90 exceeds a predetermined maximum
external load.
The unlatch signal provided to the tailgate latch actuator 74 by
the command device 230 may be terminated if an external force
and/or mass is applied to the tailgate 90. In some embodiments, the
command device 230 may provide the unlatch signal to the tailgate
latch actuator 74 and subsequently terminate the unlatch signal to
the tailgate latch actuator 74, such that if the unlatch force
applied to the tailgate latch 70 by the tailgate latch actuator 74
does not overcome the internal resistance of the tailgate latch 70,
the tailgate 90 will remain in a closed position. In other
embodiments, the electronic control unit 200 may determine that the
tailgate 90 has not opened following an unlatching operation by the
tailgate latch actuator 74, for example by sensing no speed signal
from the speed sensor 210, as depicted in FIG. 1. The electronic
control unit 200 may terminate the unlatch signal to the tailgate
latch actuator 74. In some embodiments, the command device 230 may
be configured to "time-out" the unlatch signal as to stop
transmitting the unlatch signal to the tailgate latch actuator 74
after a pre-determined time. Embodiments of the vehicle 80
incorporating the tailgate latch actuator 74 may passively manage
remote actuation of the vehicle tailgate 90 by restricting remote
actuation. As such, the tailgate latch actuator 74 that manages
remote actuation of the vehicle tailgate 90 as to control remote
actuation of the vehicle tailgate 90 may do so without the
inclusion of sensors to determine if an external force and/or mass
exceeding a predetermined maximum external load is applied to the
vehicle tailgate 90 in the opening direction.
Referring to FIG. 2, one embodiment of the vehicle 80 may include a
tailgate assist damper 98 coupled to a sidewall 92 of the vehicle
80 and to the tailgate 90. The tailgate assist damper 98 applies an
assist force to the tailgate 90 in a direction that reduces the
force required to be input by a user to reposition the tailgate 90
between open and closed positions. In the embodiment depicted in
FIG. 2, the tailgate assist damper 98 applies a force to the
tailgate 90 in a direction corresponding to rotating the tailgate
90 from an open position to a closed position. Thus, the tailgate
assist damper 98 shown in FIG. 2 reduces the opening speed of the
tailgate 90 and/or reduces the force required to be applied by a
user to rotate the tailgate 90 to the closed position. An example
of such a tailgate assist damper 98 includes the Tailgate
Lift-Assist available from Multimatic Inc. of Markham, Ontario,
Canada.
Referring now to FIG. 3, components of the tailgate energy
management system 100 of FIG. 2 are shown in greater detail. The
tailgate assist damper 98 is coupled to the tailgate 90 through a
linkage 95 that connects to a hinge 94. The linkage 95 and the
hinge 94 transmit torque from the tailgate assist damper 98 to the
tailgate 90. The rotatable drum 124 of the retractable cable
assembly 120 is coupled to the sidewall 92 of the vehicle 80. As
depicted in FIG. 3 and shown in greater detail in FIG. 4, the
rotatable drum 124 is mounted to the sidewall 92 with a hub 132
that interfaces with the governor 110. When the electronic control
unit 200 determines the opening speed of the tailgate 90 needs to
be reduced, the governor 110 interacts with the hub 132 to apply a
governing force to the rotatable drum 124, which, in turn, limits
the opening speed of the tailgate 90. In some embodiments, the
retractable cable assembly 120 may further include a pre-wound
spring 126 that applies a coiling force to the rotatable drum 124.
The coiling force is applied in a direction that assists with
winding the cable 122 about the rotatable drum 124 as the tailgate
90 rotates from an open position to a closed position.
Referring now to FIGS. 2 and 3, by controlling the opening speed of
the tailgate 90, the tailgate energy management system 100 controls
a maximum amount of kinetic energy that the tailgate 90 carries as
the tailgate 90 rotates from a closed position to an open position.
By limiting the amount of kinetic energy carried by the tailgate 90
as it opens, damage to the tailgate 90 and/or a surrounding object
may be minimized if the tailgate 90 contacts the surrounding object
while opening.
Specifically, as the tailgate 90 rotates to an open position, the
tailgate assist damper 98 applies torque to the tailgate 90 that
decreases the opening speed of the tailgate 90. Simultaneously, the
cable 122 begins to pay out from the rotatable drum 124. The speed
sensor 210 senses that the cable 122 is being paid out and
transmits a speed signal to the electronic control unit 200
indicative of the opening speed of the tailgate 90. In the
embodiment depicted in FIGS. 2 and 3, the speed sensor 210 measures
the speed of rotation of the rotatable drum 124. Because the
rotatable drum 124 pays out the cable 122 coupled to the tailgate
90, the speed of rotation of the rotatable drum 124 corresponds to
the opening speed of the tailgate 90.
The electronic control unit 200 receives the speed signal from the
speed sensor 210. A processor in the electronic control unit 200
processes the speed signal from the speed sensor 210, and, based on
a computer readable and executable instruction set stored in
memory, determines if the opening speed of the tailgate 90 is
approaching a pre-determined maximum opening speed. The
pre-determined maximum opening speed of the tailgate 90 may be
calculated and stored in the memory of the electronic control unit
200. The maximum opening speed may be determined such that the
kinetic energy of the tailgate 90 does not exceed a certain
threshold of kinetic energy, for example about 10 joules. The
opening speed of the tailgate 90 and the weight of the tailgate 90
determine the kinetic energy of the tailgate 90 as the tailgate 90
rotates to the open position.
The electronic control unit 200 compares the speed signal received
from the speed sensor 210 to a stored value to determine whether
the opening speed of the tailgate 90 is approaching or exceeds the
pre-determined maximum opening speed. In some embodiments, the
electronic control unit 200 may include a control variable that is
stored in memory of the electronic control unit 200. The
instruction set of the electronic control unit 200 instruct the
processor to compare the speed signal that is received from the
speed sensor 210 to the control variable stored in memory. In other
embodiments, the electronic control unit 200 may include a lookup
table stored in memory that correlates the speed signal transmitted
by the speed sensor 210 to an opening speed of the tailgate 90. In
yet other embodiments, the instruction set may include a conversion
variable that correlates the speed signal transmitted by the speed
sensor 210 to an opening speed of the tailgate 90. Thus, the
electronic control unit 200 determines if the opening speed of the
tailgate 90 is approaching a pre-determined maximum opening speed
by comparing the speed signal transmitted by the speed sensor 210
to a stored value stored within the electronic control unit
200.
In the embodiment of vehicles 80 where the speed sensor 210 uses a
Hall Effect sensor, the electronic control unit 200 may evaluate
the time intervals between voltage peaks that are induced into the
speed sensor 210 by rotating permanent magnets coupled to the
retractable cable assembly 120. The time intervals between voltage
peaks measured by the Hall Effect sensor correspond to the speed of
rotation of the permanent magnets and, in turn, the opening speed
of the tailgate 90. In addition, the electronic control unit 200
may evaluate the speed signal that is received from the speed
sensor 210 to calculate the angular opening speed of the tailgate
90.
As the opening speed of the tailgate 90 approaches the maximum
opening speed, the electronic control unit 200 processes the speed
signal from the speed sensor 210 based on the instruction set and
determines that the tailgate 90 is approaching the pre-determined
maximum opening speed. The electronic control unit 200 transmits a
control signal to the governor 110 to actuate the governor 110. The
governor 110 receives the control signal from the electronic
control unit 200 and, in turn, applies a governing force to the
tailgate 90. The governing force slows the opening speed of the
tailgate 90. In the embodiment depicted in FIGS. 2 and 3, the
governor 110 is coupled to the rotatable drum 124 by the hub 132.
The governor 110, therefore, applies the governing force to hub 132
such that the speed of rotation of the rotatable drum 124, and the
corresponding speed that the rotatable drum 124 pays out the cable
122, is limited. Thus, the governor 110 slows the opening speed of
the tailgate 90.
In embodiments of the vehicle 80 that include electromechanical
brakes as the governor 110, the electronic control unit 200 may
transmit a control signal to the governor 110 to intermittently
apply and release the electromechanical brake, such that the
governing force is "pulsed," thereby decreasing the opening speed
of the tailgate 90.
In some embodiments, the tailgate assist damper 98 and the tailgate
energy management system 100 may work in conjunction with one
another to control the opening speed of the tailgate 90. In
general, tailgate assist dampers 98 provide a directional force to
tailgates 90 that decreases the opening speed of the tailgate 90
and reduces the force a user must apply to rotate the tailgate 90
from an open position to a closed position. Under normal operating
conditions, the tailgate assist damper 98 may control the opening
speed of the tailgate 90 without exceeding a predetermined maximum
opening speed. However, under certain operating conditions, for
example, with the vehicle 80 parked on an incline, at elevated
temperatures, and/or with a worn tailgate assist damper 98, the
tailgate 90 may be prone to open at speeds that exceed the
pre-determined maximum opening speed. Under conditions such as
these, the tailgate energy management system 100 and the tailgate
assist damper 98 operate in conjunction with one another to control
the opening speed of the tailgate 90 such that the tailgate 90
opens without intervention from a user, and opens without exceeding
the pre-determined maximum opening speed.
Conversely, under certain operating conditions, for example, with
the vehicle 80 parked on an incline, the tailgate 90 may be prone
to open at a speed that does not exceed the maximum opening speed.
Under such conditions, the tailgate assist damper 98 will apply
torque to the tailgate 90 that prevents the tailgate 90 from
opening at a speed greater than the maximum opening speed. In these
conditions, the speed sensor 210 continues to transmit a speed
signal to the electronic control unit 200. The electronic control
unit 200 calculates that the opening speed of the tailgate 90 and
determines that the opening speed of the tailgate 90 is not
approaching the pre-determined maximum opening speed. Because no
governing force is required to slow the opening speed of the
tailgate 90 below the pre-determined maximum opening speed, the
electronic control unit 200 does not transmit a control signal to
the governor 110 to actuate the governor 110. Thus, the tailgate
energy management system 100 does not apply a governing force to
the tailgate 90 to reduce the opening speed of the tailgate 90.
Alternatively, or in addition to the tailgate assist damper 98, the
vehicle 80 may include torsion springs (not shown) that apply a
direction force to the tailgate 90. The directional force applied
by the torsion springs is applied to the tailgate 90 is a direction
that decreases the opening speed of the tailgate 90 and reduces the
force a user must apply to rotate the tailgate 90 from an open
position to a closed position.
Another embodiment of a vehicle 80 including a tailgate energy
management system 100 is depicted in FIGS. 5 and 6. In this
embodiment, the tailgate energy management system 100 includes a
hub 132 located within one of the sidewalls 92 of the vehicle 80.
In the depicted embodiment, the hub 132 is coupled to the tailgate
90 with a reduction gear set 130, a linkage 95, and a hinge 94. The
hub 132 is coupled to the governor 110, allowing the governor 110
to apply the governing force to the tailgate 90 by applying the
governing force directly to the hub 132.
Similar to the embodiment described with reference to FIGS. 2 and 3
above, the tailgate energy management system 100 depicted in FIGS.
5 and 6 controls a maximum amount of kinetic energy that may be
carried by the tailgate 90 as the tailgate 90 rotates from a closed
position to an open position. The speed sensor 210 transmits a
speed signal indicative of the opening speed of the tailgate 90 to
the electronic control unit 200. In the embodiment depicted in
FIGS. 5 and 6, the speed sensor 210 measures the speed of rotation
of one of the members of the reduction gear set 130. Because the
reduction gear set 130 is coupled to the tailgate 90 by the linkage
95 and the hinge 94, the speed of rotation of the members of the
reduction gear set 130 corresponds to the opening speed of the
tailgate 90.
The electronic control unit 200 receives the speed signal from the
speed sensor 210. The electronic control unit 200 evaluates the
speed signal from the speed sensor 210 to determine if the opening
speed of the tailgate 90 is approaching a pre-determined maximum
opening speed. As the opening speed of the tailgate 90 approaches
the maximum opening speed, the electronic control unit 200
transmits a control signal to the governor 110 to actuate. The
governor 110 receives the control signal from the electronic
control unit 200 and applies a governing force to the tailgate 90.
The governing force slows the opening speed of the tailgate 90. In
the embodiment depicted in FIGS. 5 and 6, the governor 110 applies
the governing force to the hub 132, such that the speed of rotation
of the hub 132, and the corresponding speeds of the reduction gear
set 130, are limited. Thus, the governor 110 slows the opening
speed of the tailgate 90.
Vehicles 80 that include tailgate energy management systems 100 as
described herein may be included with other components that allow
the tailgate 90 to be actuated by a user while the user is
positioned at a location remote from the tailgate 90 and/or the
vehicle 80. An example of such an application is a vehicle 80 that
includes a remote keyless entry system that allows a user to
trigger operation of tailgate 90. A vehicle 80 having a remote
keyless entry system may allow the user to remotely rotate the
tailgate 90 from a closed position to an open position. By limiting
the maximum kinetic energy that the tailgate 90 may carry as it
opens, the tailgate energy management system 100 may reduce the
likelihood of damage due to contact of the tailgate 90 with any
surrounding object as the tailgate 90 is remotely opened.
Vehicles 80 that include remote keyless entry systems and tailgate
energy management systems 100 as described hereinabove may include
control logic that disables the remote keyless entry system in the
event that the tailgate energy management system 100 is not
reducing the opening speed of the tailgate 90. In one embodiment,
the control logic may transmit a command to disable the remote
keyless entry system from performing subsequent opening operations
if the electronic control unit 200 determines that the opening
speed of the tailgate 90 exceeds the maximum opening speed.
Additionally, as a user may remove and reattach the tailgate 90
from the vehicle 80, the user may reattach the tailgate 90 to the
vehicle 80 without properly connecting the tailgate energy
management system 100 to the tailgate 90. The electronic control
unit 200 may include control logic stored in memory that evaluates
the opening speed of the tailgate 90. If the tailgate energy
management system 100 is not properly connected to the tailgate 90,
the speed sensor 210 may not measure an opening speed of the
tailgate 90 after the tailgate 90 has been triggered to open by the
remote keyless entry system. In the event no opening speed is
measured but an opening operation has been triggered by the remote
keyless entry system, the electronic control unit 200 may disable
the remote keyless entry system from triggering subsequent opening
operations.
Alternatively, or in addition, in vehicles 80 that include the
tailgate energy management system 100 as depicted in FIGS. 2 and 3,
the electronic control unit 200 may be connected to a retraction
sensor (not shown) that evaluates whether any cable 122 is paid out
from the rotatable drum 124. In general, when connecting the cable
122 to the tailgate 90, cable 122 may be paid out from the
rotatable drum 124. Thus, if the retraction sensor senses that no
cable 122 is paid out (i.e., the cable 122 is fully wound along the
rotatable drum 124), the electronic control unit 200 may disable
the remote keyless entry system from triggering an opening
operation.
Vehicles 80 may also include a tailgate position sensor (not shown)
that senses if the tailgate 90 is located in a closed position and
transmits a tailgate position signal to the electronic control unit
200. If the electronic control unit 200 determines that the
tailgate 90 is located in an open position, the electronic control
unit 200 may disable the remote keyless entry system from
triggering an opening operation.
Vehicles 80 that include tailgate energy management systems 100
according to the present disclosure allow a user to manually rotate
the tailgate 90 between open and closed positions without requiring
operation of the tailgate energy management systems 100, such as
when the kinetic energy of the tailgate 90 does not exceed the
threshold energy as the user manually rotates the tailgate 90
between open and closed positions. Thus, a user may manually open
the tailgate 90 of the vehicle 80 without having to disconnect the
tailgate energy management system 100 from the tailgate 90.
Additionally, the tailgate energy management system 100 may not add
significant resistance to rotating the tailgate 90 to the closed
position from the open position. Thus, closing the tailgate 90 by
the user may not be more difficult as compared to a vehicle 80 that
does not include a tailgate energy management system 100.
It should now be understood that vehicles having tailgates may
include tailgate energy management systems that limit the opening
speed of the tailgates. By limiting the opening speed of the
tailgates, the amount of energy the tailgates carry as they open
may be controlled such that the tailgates cannot impart significant
force on surrounding objects. The tailgate energy management
systems apply governing forces to the tailgates that control
opening speed of the tailgates while allowing a user to manually
open and close the tailgate of the vehicle. The tailgate energy
management systems may work in conjunction with tailgate assist
dampers, which assist both with opening and closing tailgates.
It is noted that the terms "substantially" and "about" may be
utilized herein to represent the inherent degree of uncertainty
that may be attributed to any quantitative comparison, value,
measurement, or other representation. These terms are also utilized
herein to represent the degree by which a quantitative
representation may vary from a stated reference without resulting
in a change in the basic function of the subject matter at
issue.
While particular embodiments have been illustrated and described
herein, it should be understood that various other changes and
modifications may be made without departing from the spirit and
scope of the claimed subject matter. Moreover, although various
aspects of the claimed subject matter have been described herein,
such aspects need not be utilized in combination. It is therefore
intended that the appended claims cover all such changes and
modifications that are within the scope of the claimed subject
matter.
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